Electric breast pumps are known in the art. There is disclosed in U.S. Pat. No. 7,070,400 to Greter a diaphragm suction pump without pump chamber dead space. In particular, the '400 patent is directed to a diaphragm pump wherein the pump diaphragm is driven by an electric motor crank mechanism by means of a connecting rod and spans a pump chamber provided in a base plate. The pump chamber walls are provided with a conically widening profile and the various parts are configured such that the diaphragm bears substantially tightly against the entire pump chamber wall along the sides and at a top dead center position of the connecting rod will result in a position where there is substantially no dead space. It has been found that this particular arrangement is undesirable since there is no means to break the vacuum between the diaphragm and the cylinder pump head upon reciprocation of the diaphragm, resulting in “vacuum lock”.
U.S. Pat. No. 6,547,756 to Greter et al. discloses a breast pump which can be programmed to generate a plurality of different milk expression sequences. In one embodiment of the invention, a motorized pump is provided with a microprocessor controller.
Also disclosed in pending applications are various features for breast pumps. In this regard, there is disclosed in United States Patent Application Publication No. 2004/0024351 (U.S. patent application Ser. No. 10/413,463) to Greter et al. a breast pump that generates a let-down or stimulation phase and a milk expression phase. See, also, United States Patent Application Publication No. 2007/0292276 (U.S. patent application Ser. No. 11/662,683) to Stutz et al. entitled “Membrane Pump With Bleed Valve.” The Stutz et al. application discloses a vacuum pump with a bleed valve which opens partially at an initial stage and later opens to a greater extent during a pump cycle.
While various features and control schemes have been disclosed in the art, electric breast pumps are typically expensive and relatively difficult to operate. There is provided in accordance with the present invention an easy to use, economical breast pump system which provides superior levels of comfort and adjustability without complex operating modes.